Apparatus and Method for Generating Audio Subband Values and Apparatus and Method for Generating Time-Domain Audio Samples

Abstract

An embodiment of an apparatus for generating audio subband values in audio subband channels has an analysis windower for windowing a frame of time-domain audio input samples being in a time sequence extending from an early sample to a later sample using an analysis window function having a sequence of window coefficients to obtain windowed samples. The analysis window function has a first group of window coefficients and a second group of window coefficients. The first group of window coefficients is used for windowing later time-domain samples and the second group of window coefficients is used for windowing an earlier time-domain samples. The apparatus further has a calculator for calculating the audio subband values using the windowed samples.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a U.S. national entry of PCT Patent Application Serial No. PCT / EP2007 / 009199 filed 23 Oct. 2007, and claims priority to U.S. provisional patent application No. 60 / 862,954 filed on Oct. 25, 2006, which is incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTION[0002]Embodiments of the present invention relate to an apparatus and method for generating audio subband values, an apparatus and a method for generating time-domain audio samples and systems comprising any of the aforementioned apparatuses, which can for instance be implemented in the field of modern audio encoding, audio decoding or other audio transmission-related applications.[0003]Modern digital audio processing is typically based on coding schemes which enable a significant reduction in terms of bit rates, transmission bandwidths and storage space compared to a direct transmission or storage of the respective audio data. This is achieved...

AI Technical Summary

Benefits of technology

[0007]According to an embodiment, an apparatus for generating complex-valued audio subband values in audio subband channels may have: an analysis windower for windowing a frame of time-domain audio input samples being in a time sequence extending from an early sample to a later sample using an analysis window function having a sequence of window coefficients to obtain windowed samples, the analysis window function having a first group of window coefficients having a first portion of the sequence of window coefficients and a second group of window coefficients having a second portion of the sequence of window coefficients, the first portion having less window coefficients than the second portion, wherein an overall energy value of the window coefficients in the first portion is higher than an overall energy value of the window coefficients of the second portion, wherein the first group of window coefficients is used for windowing later time-domain samples and the second group of window coefficients is used for windowing earlier time-domain samples; and a calculator for calculating the audio subband values using the windowed samples, wherein the calculator has a time / frequency converter adapted to generating the audio subband values such that all subband values based on one frame of windowed samples represent a spectral representation of the windowed samples of the frame of windowed samples, and wherein the time / frequency converter is adapted to generating complex-valued audio subband values.

Problems solved by technology

Very often, higher qualities demand higher bit rates, an increased computational complexity and a higher storage requirement for the corresponding encoded audio data.

As a consequence, the delay imposed by the audio encoding and decoding poses a further constraint in terms of the previously mentioned parameters when balancing the needs and the costs of different coding schemes having a specific field of application in mind.

However, in many cases, compromises may have to be taken in terms of different parameters such as bit rate, computational complexity, memory requirements, quality and delay.

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